Improved formulation of NEMguard, a garlic-based nematicide, could also be used to safeguard other crops in the future
For a while now fresh produce growers have faced the terrifying prospect of losing some of their key crop protection products, as Europe’s stringent new pesticide laws mean many conventional chemical pesticides are in danger of being removed from the market over the next few years.
While this has caused widespread concern, the situation is not all “doom and gloom” as new and residue-free products, as well as improved formulations of existing products, continue to be released onto the market.
The start of this year, for example, has seen the release of a new formulation of crop protection firm Certis’s garlic-based nematicide – NEMguard – which targets parasitic nematode pests and features an active substance extracted from garlic.
The new formulation – NEMguard DE – is being marketed by Certis, a Cambridgeshire-based crop protection business. Last autumn the firm teamed up with the product’s manufacturers, Norfolk’s Ecospray, to help promote NEMguard DE to a larger number of growers.
Robert Lidstone, Certis’ marketing and business development manager, says: “Growers of carrots and parsnips are turning to NEMguard as a viable alternative to carbamate chemistry. The active substance in NEMguard is a garlic extract – a naturally derived product, which benefits from no MRL (maximum residue limit) or harvest interval.”
NEMguard is already registered with the UK’s Chemicals Regulation Directorate (CRD) for use on parsnip and carrot crops. Nematodes are the most common cause of deformities in these root vegetables. The microscopic worms overwinter in soil, and their feeding activity stimulates the plant cells to form galls (sores) on the roots. These galls prevent the plant from accessing adequate water and nutrients, which then stunt the plant’s growth.
Speaking to Produce Business UK, Lidstone reveals that NEMguard’s new formulation creates less dust while it is being applied and, as such, is named NEMguard DE, after “diatomaceous earth” – a rock that is easily crumbled into a powder.
He explains: “It gives very good release characteristics and is a “low-dust” formulation. It’s applied in the row of the crop rather than broadcast. So basically you put the granules where the crop is going to grow.”
In the near future, Lidstone hopes to gain registration for NEMguard to be used on other types of fresh produce crops. “Currently about 20% of the market is using it,” he says.
But the potential, not just for this crop but also for other crops in the future, is much larger.
“We therefore have to look at what other opportunities there are for other crops going forward,” Lidstone says. “We know it works, we know it’s been accepted by the market. Now we need to take the next step.”
Nematode populations are rising
The root knot nematode (Meloidogyne minor) could become the number one problem in the UK over the next decade in a broad range of horticulture crops, with numbers having increased by 300% in the last 30 years.
Guest speaker Dr Colin Fleming, principal scientific officer at the Agri-Food and Biosciences Institute in Belfast, Ireland, explained that several factors are probably significant in the increase of the nematode populations.
“The climate is changing and we are seeing warmer, wetter weather patterns that favour nematodes and are encouraging species that prefer warmth, like the root knot, to thrive,” he said. “The reduction in the number of active substances available for use in agriculture is also having an effect.”
Dr Chris Hamilton, who has been working with sulphur chemistry at the University of East Anglia for a number of years, was also a speaker at the event. There, he revealed some of the background research behind NEMguard, which can be used in combination with conventional nematicides, biological and cultural controls.
He said: “When garlic cells are ruptured and then heated, a breakdown substance is produced which contains diallyl polysulfides. These molecules are able to elicit a cascade of different changes within the metabolism of the nematode that ultimately kills them,” he explained. “These polysulfides have multi-site activity so resistance is unlikely.”
